Positively closed classes of three-valued logic generated by one-place functions
Sergey Seraphimovich Marchenkov · Discrete Mathematics and Applications · 2009
We consider the positive closure operator on the set P 3 of functions of three-valued logic. It is shown that in P 3 there are exactly 51 positively closed classes positively generated by one-place functions, 26 of these classes are generated by a single one-place function (including one of the positively precomplete in P 3 classes), and 25 classes are generated by two functions (including the class P 3 and the remaining 9 positively precomplete classes).